The U.S. Treasury Department sold $35 billion of three-year debt, $23 billion in 10-year notes and $15 billion in 30-year bonds this week to solid investor demand.

Still bearish Treasury bets paid off this week as benchmark 10-year yields touched 3 percent on Friday for the first time in about six weeks.

The amount of speculators' bearish, or short, positions in 10-year Treasury futures exceeded bullish, or long, positions by 682,684 contracts on Sept. 11, according to the CFTC's latest Commitments of Traders data.

A week earlier, speculators held 682,757 net short positions in 10-year T-note futures.

Speculative 10-year net shorts remained close to the 700,514 contracts reached in August.